1. Field of the Invention
The present invention relates to an ink jet print head, and more specifically to a continuity configuration of a laminated piezoelectric element of the head.
2. Related Art
A conventional ink jet print head includes a ceramic plate serving as a stationary plate, individual front electrodes mounted on a front surface of the ceramic plate, laminated piezoelectric elements electrically connected to the corresponding front electrodes by an electrically conductive adhesive, individual rear electrodes mounted on a rear surface of the ceramic plate, and flexible printed cable (FPC) electrically connected to the corresponding rear electrodes by soldering. The ceramic plate is formed from alumina with a plurality of through holes having a diameter of 0.25 mm. The through holes are filled with silver paste as filler, which electrically connecting the front electrode with the corresponding rear electrode. That is, the laminated piezoelectric element is electrically connected to the flexible printed cable via the front and rear electrodes and the filler.
This type of ink jet print head is formed in the following process. A green sheet is prepared and subject to calcinations to provide the ceramic plate. The plurality of through holes are formed in the ceramic plate by laser beam technique. The silver paste is applied into the through holes and also over the entire front surface of the ceramic plate, and is subject to sintering. The electrically conductive adhesive is coated over the front surface, and a block of piezoelectric element is placed thereon. The resultant product is subject to a dicing process to cut the block into the plurality of piezoelectric elements. At the same time, the silver paste on the ceramic sheet is also cut into a plurality of pieces, thereby providing the plurality of individual front electrodes.
However, the conventional ceramic plate with the above configuration has the following problems.
Firstly, when the above ceramic plate is placed in a high-temperature high-humid environment or get wet with ink, migration occurs in the front and rear electrodes. This results in continuity failure.
Secondly, a heat cycle that repeats between a room temperature and a higher temperature of 130xc2x0 C. weakens the strength of the solder joint between the flexible printed cable and the rear electrodes, thereby causing disconnection.
It is an objective of the present invention to overcome the above problems and also to provide an ink jet print head in which continuity failure is effectively prevented and a method for producing the same.
In order to achieve the above and other objects, there is provided an ink jet print head including a stationary plate having a first surface and a second surface, a first electrode provided on the first surface, and a laminated piezoelectric element mounted on the first surface. The laminated piezoelectric element is electrically connected to the first electrode via an electrically conductive adhesive. The first electrode is formed of one of tungsten and molybdenum-manganese alloy.
There is also provided a producing method of producing an ink jet print head. The method includes the steps of a) forming a plurality of through holes in a green sheet, the through holes having first ends opened to a first surface of the green sheet and second ends opened to a second surface of the green sheet, b) filling in the through holes with filler, wherein the filler is one of tungsten and molybdenum-manganese alloy, c) forming a plurality of first electrodes from one of tungsten and molybdenum-manganese alloy on the first ends, d) forming a plurality of second electrodes from one of tungsten and molybdenum-manganese alloy on the second ends, e) plating the first and second electrodes with gold, f) placing a laminated-piezoelectric block on the first surface, g) applying an electrically conductive adhesive over the first surface and the first electrodes, and h) dicing the laminated-piezoelectric block into a plurality of laminated piezoelectric elements.